• Thermally-Induced Phase Separation Mechanism Study for Semicrystalline Polymeric Membrane Formation
  • Yeom MO, Song K, Kim SS
  • 결정성 고분자막의 제조를 위한 열유도 상분리 기구에 관한 연구
  • 염민오, 송기국, 김성수
Abstract
The thermally-induced phase separation mechanism for isotatic polypropylene membrane formation was investigated for the system isotactic polypropylene and diphenyl ether. The degree of supercooling into liquie-liquid phase separation region of the phase diagram affected the size and growth rate of the droplets. Increasing the polymer content affected the solution viscosity and interaction parameter to result in the decreases in the size and growth rate of the droplets. Droplet growth rate followed the equation proposed by Furukawa, and the droplet growth kinetics was well described by the theories for coarsening and coalescence. Equilibrium droplet size was estimated by Young-Laplace equation and it was in good agreement with the experimental data. At low quench temperatures, as the polymer content increased and the quench temperature decrased the number of initial iPP spherulites and the spherulite growth rate tend to increase due to the increase of the density of nucleation. Polymer crystallization interfered with the droplet growth at lower quench temperatures. Decreasing of quench temperature resulted in the increase of isothermal crystallization rate and the decrease of crystallization completion time. Avrami exponent values decreased as the quench temperature decreased, which means the decrease of dimension number of crystal and shifted the nucleation mechanism from sporadic to instantaneous.

열유도 상분리 공정을 이용한 isotactic polypropylene (iPP) 막의 제조를 위하여 iPP와 diphenyl ether 계에 대한 상분리 기구를 고찰하였다. 상분리도의 액-액 상분리 지역내에서 과냉각(supercooling)의 정도는 droplets의 크기와 성장 속도에 영향을 미쳤다. 고분자 양이 증가하면 용액의 점도와 상호작용 파라미터의 영향에 의해 droplets의 크기와 성장 속도가 감소되는 결과를 보였다. Droplet의 성장 속도는 Furukawa에 의해 제안된 이론과 부합하였고 droplet의 성장 속도론은 coarsening과 coalescence에 대한 식에 적합함을 보였다. Young-Laplace 식에 의해 추정 계산된 평형 droplet의 크기는 실험값과 잘 일치함을 보였다. 낮은 온도에서 고분자 조성이 증가할수록 그리고 결정화 온도가 감소할수록 핵생성 밀도가 커짐으로써 초기의 iPP 구정 (spherulite)의 수가 증가하였고 구정 성장 속도도 증가하였다. 낮은 급냉 온도에서는 고분자의 결정화가 drop-let의 성장을 간섭하였다. 등온 고분자 결정화 실험에 의하여 급냉 온도가 감소함에 따라 결정화가 진행되는 속도는 증가하고 등온 결정화 완료 시간은 감소하였다. Avrami 지수값은 결정화 온도가 낮아질수록 감소하여 결정의 차원수가 감소하고 nucleation 기구는 sporadic에서 instantaneous로 전환되었다.

Keywords: thermally-induced phase separation; semicrystalline polymer membrane; isotactic polypropylene; diphenyl ether; droplet size; crystallization

References
  • 1. Howell JA, Sanchez V, Field RWMembranes in bioprocessing, Chapman & Hall, London, Chap. 1-2 (1993)
  •  
  • 2. Degen PJ, Lee JU.S. Patent, 5,492,781 (1996)
  •  
  • 3. Kesting RESynthetic Polymeric Membranes, John Wiley & Sons, New York (1985)
  •  
  • 4. Lloyd DR, Kim SS, Kinzer KE, J. Membr. Sci., 64, 13 (1991)
  •  
  • 5. Olabisi O, Robeson LM, Shaw MTPolymer-Polymer Miscibility, Academic Press, New York, Chap. 2 (1979)
  •  
  • 6. Chan JW, ACTA Metallurgica, 9, 795 (1961)
  •  
  • 7. Song SW, Torkelson JM, Macromolecules, 27(22), 6389 (1994)
  •  
  • 8. Tsai FJ, Torkelson JM, Macromolecules, 23, 775 (1990)
  •  
  • 9. Nojima S, Shiroshita K, Nose T, Polym. J., 14, 289 (1982)
  •  
  • 10. Kim SS, Lloyd DR, Kinzer KE, J. Membr. Sci., 64, 1 (1991)
  •  
  • 11. Lloyd DR, Kinzer KE, Tseng HS, J. Membr. Sci., 52, 239 (1990)
  •  
  • 12. Burghardt WR, Macromolecules, 22, 2482 (1989)
  •  
  • 13. Vandewitte P, Dijkstra PJ, Vandenberg JW, Feijen J, J. Membr. Sci., 117(1-2), 1 (1996)
  •  
  • 14. Mcguire KS, Laxminarayan A, Martula DS, Lloyd DR, J. Colloid Interface Sci., 182(1), 46 (1996)
  •  
  • 15. Laximinarayan ADissertation, The University of Texas at Austin (1994)
  •  
  • 16. Laxminarayan A, Mcguire KS, Kim SS, Lloyd DR, Polymer, 35(14), 3060 (1994)
  •  
  • 17. Lim G, Lloyd DR, Polym. Eng. Sci., 33, 513 (1993)
  •  
  • 18. Avrami M, J. Chem. Phys., 7, 1103 (1939)
  •  
  • 19. Avrami M, J. Chem. Phys., 9, 177 (1941)
  •  
  • 20. Andreas JM, Hauser EA, Tucker WB, J. Phys. Chem., 42, 1001 (1938)
  •  
  • 21. Lee HK, Myerson AS, Levon K, Macromolecules, 25, 4002 (1992)
  •  
  • 22. Zryd JL, Burghardt WR, J. Appl. Polym. Sci., 57(12), 1525 (1995)
  •  
  • 23. McGuire K, Lloyd DR, Lim G, J. Membr. Sci., 79, 27 (1993)
  •  
  • 24. Wang YF, Lloyd DR, Polymer, 34, 4740 (1993)
  •  
  • 25. Cha BJ, Char K, Kim JJ, Kim SS, Kim CK, J. Membr. Sci., 108(3), 219 (1995)
  •  
  • 26. Miller CM, Neogi PInterfacial Phenomena, p. 1, Marcel Dekker, Inc., New York (1985)
  •  
  • 27. CRC Handbook of Chemistry and Physics, 75th Edn, D.R. Lide, Ed., CRC Press, Boca Raton (1995)
  •  
  • 28. Adamson AWPhysical Chemistry of Surfaces, 5th ed., Wiley-Interscience, New York (1990)
  •  
  • 29. Van Krevelen DWProperties of Polymers, 2nd ed., Elsevier,Amsterdam (1976)
  •  
  • 30. Lifshitz IM, Slyozov VV, J. Phys. Chem. Solids, 19, 35 (1961)
  •  
  • 31. Siggia ED, Phys. Rev., A, 20, 59 (1979)
  •  
  • 32. Binder K, Stauffer D, Phys. Rev. Lett., 33, 1006 (1974)
  •  
  • 33. Wong NC, Knobler CM, J. Chem. Phys., 69, 725 (1978)
  •  
  • 34. Chou YC, Goldburg WI, Phys. Rev., A, 20, 2105 (1979)
  •  
  • 35. Furukawa H, Adv. Phys., 34, 703 (1985)
  •  
  • 36. Alwattari AAPh.D. Dissertation, The University of Texas at Austin (1994)
  •  
  • 37. Alger Mark SMPolymer Science Dictionary, p. 29, Elsevier Science Publishers, New York (1989)
  •  
  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2024 Impact Factor : 0.6
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This Article

  • 1999; 23(2): 320-327

    Published online Mar 25, 1999